There should be an online solution which would be simple and universal for new users to view 2D DGN contents without need to install anything and would be OS independent. Bentley View for example is too complicated and at same time too limited for new users, it requires prior Microstation experience to be usable or requires training. "DGN preview handler" has issues, lacks basic tools and is not configurable. Mobile imodels could be usable on mobile devices but it lacks dgn to imodel on-the-fly conversion so there is no need for prior conversion process if receive DGN by email for example.